The council found that even when drivers said they were using their cellphones at the time of a crash, that admission was not recorded in accident reports that have been compiled for use in the national debate on distracted driving.

"We believe the number of crashes involving cellphone use is much greater than what is being reported," said Janet Froetscher, the council's president. "Many factors, from drivers not admitting cellphone use, to a lack of consistency in crash reports being used to collect data at the scene, make it very challenging to determine an accurate number."

Researchers reviewed 180 fatal crashes over a three-year period where there was evidence that the driver was using a cellphone. In one of those years, 2011, only 52 percent of the crashes were recorded in the national database as cellphone-related. The report also found wide variation among states in their reporting of fatal crashes as cellphone-related. In 2011, Tennessee reported 93 fatalities while New York recorded one and Nevada reported none.

"The public should be aware that cellphone-involved fatal crashes are not accurately being reported," said Bill Windsor, associate vice president at Nationwide Mutual Insurance Co., which helped fund the study.

The council estimated that one-quarter of all crashes involved cellphone use.

Associated Press

Sault Ste. Marie students take the KDR Challenge in 2011 and sign a banner on cellphone and driving dangers in memory of a Michigan teen who crashed while on a cellphone. Her accident was chalked up to mistakes made by a novice driver.